The dynamic regulation effect in X@Fe-N4/C electrocatalyst for the sequential oxygen reduction reaction

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Vol. 713; p. 136512
• Main Authors: Zhang, Xiaoming, Wang, Suli, Xia, Zhangxun, Li, Huanqiao, Yu, Shansheng, Sun, Gongquan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 20.05.2025
• Subjects: catalytic activity; density functional theory; Dynamic regulation; electrochemistry; Halogen atom; Non-bonding coordination; Oxygen reduction reaction; Sequential catalytic; Sequential catalytic; Non-bonding coordination; Dynamic regulation; Oxygen reduction reaction; Halogen atom
• ISSN: 0927-7757
• DOI: 10.1016/j.colsurfa.2025.136512

Metal-nitrogen-carbon based single atom catalysts (SACs) have been the subject of oxygen reduction reaction (ORR) electrocatalysts for electrochemical devices. Nevertheless, the scaling relationship of ΔG*OOH, ΔG*OH and ΔG*O represents a significant obstacle to further enhancement of ORR efficiency for SACs. Accordingly, a confinement model X@M-N4/C electrocatalyst was constructed. The density functional theory calculations demonstrate that the overpotential of Br@Fe-N4/C54 (0.47 V vs. RHE) for ORR is significantly lower than that of Fe-N4/C54 (0.67 V vs. RHE). The variation in distance between the Br and Fe atoms during the ORR process provides evidence that supports the hypothesis that the Br atom regulates the Fe-N4 active center, through in-situ dynamic non-bonding coordination (dFe-Br>3 Å). The confined Br atom results in an increase in ΔG*OH and a decrease in ΔG*O. This results in a disruption of the linear relationship and a reduction in the overpotential associated with the rate-determining elementary reaction (*O+H++e-→*OH). The Fe-N4 active center facilitates the sequential ORR catalytic process through in-situ dynamic regulation of the trapped Br atom. This conclusion is also applicable to Br@Fe-N4/graphene and Br@Fe-N4/CNT. The findings of our research represent a significant advancement in the field of enhancing the performance of SACs for multi-electron electrocatalytic reactions. [Display omitted] •The enhanced ORR activity of Br@Fe-N4/C is attributable to a sequential catalytic process.•The dynamic regulation of Fe-N4 through the disrupted SR of ΔGads is achieved by non-bonding Br coordination.•The incorporation of a Br atom within C60 has been demonstrated to enhance stability.